Centrifugal blower having auxiliary radial inlet

ABSTRACT

A centrifugal blower includes a housing, a cover, and an impeller. The housing includes a peripheral wall delimiting an inner space. The peripheral wall further includes a first sidewall and a second sidewall respectively at two ends thereof. A radial air outlet is defined between the first sidewall and the second sidewall of the peripheral wall. A cover includes an axial air inlet communicated with the inner space of the housing. An impeller is rotatably mounted in the inner space of the housing and aligned with the axial air inlet. At least one auxiliary radial air inlet is defined in the peripheral wall and adjacent to one of the first sidewall and the second sidewall. When the impeller turns, an axial airflow is sucked into the inner space via the axial air inlet and an auxiliary radial airflow is sucked into the inner space via the auxiliary radial air inlet.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a centrifugal blower. In particular, the present invention relates to a centrifugal blower having at least one auxiliary radial inlet for increasing the air inlet amount.

2. Description of Related Art

FIG. 1 illustrates a conventional centrifugal blower (or heat dissipating fan) comprising a housing 1, a cover 2, and an impeller 3. The housing 1 includes a radial air outlet 11 and the cover 2 includes an axial air inlet 21. The impeller 3 is rotatably mounted in the housing 1. When the impeller 3 turns, axial airflow is sucked into the housing 1 via the axial air inlet 21. The direction of the axial airflow is changed and the airflow is outputted via the radial air outlet 11 for dissipating heat of an object. However, in use, a limited amount of air is sucked by the impeller 3 from top of the cover 2. The air surrounding a periphery of the housing 1 is not utilized. The air inlet amount and the wind pressure could not be increased.

Taiwan Utility Model Publication No. 444897 discloses a centrifugal blower that has a housing without axial air inlet. Instead, the housing of the centrifugal blower includes at least one radial air inlet and a radial air outlet. The radial air inlet allows suction of ambient air surrounding the housing. However, the airflow may enter and leave the housing via the radial air inlet at the same time, resulting in turbulence and thus failing to provide the expected heat-dissipating effect.

OBJECTS OF THE INVENTION

An object of the present invention is to provide a centrifugal blower with increased air inlet amount.

Another object of the present invention is to provide a centrifugal blower with improved air inlet smoothness.

A further object of the present invention is to provide a centrifugal blower with lowered air suction noise.

SUMMARY OF THE INVENTION

In accordance with an aspect of the present invention, a centrifugal blower comprises a housing, a cover, and an impeller. The housing includes a peripheral wall delimiting an inner space. The peripheral wall further includes a first sidewall and a second sidewall respectively at two ends thereof. A radial air outlet is defined between the first sidewall and the second sidewall of the peripheral wall. A cover includes an axial air inlet communicated with the inner space of the housing. An impeller is-rotatably mounted in the inner space of the housing and aligned with the axial air inlet. At least one auxiliary radial air inlet is defined in the peripheral wall and adjacent to one of the first sidewall and the second sidewall.

When the impeller turns, an axial airflow is sucked into the inner space via the axial air inlet and an auxiliary radial airflow is sucked into the inner space via the auxiliary radial air inlet.

A portion of the peripheral wall adjacent to the first sidewall delimiting the radial air outlet is an air-driving starting point. Another portion of the peripheral wall adjacent to the second sidewall delimiting the radial air outlet is an air-driving end point. The auxiliary air inlet is adjacent to the air-driving starting point.

In an embodiment, the housing is a snail shell-like structure and the impeller is eccentrically mounted in the inner space. The first sidewall delimiting the radial air outlet is closer to the impeller than the second sidewall delimiting the radial air outlet.

In an embodiment, the auxiliary radial air inlet is a rectilinear slit. In another embodiment, the auxiliary radial air inlet is an inclined slit. In a further embodiment, the auxiliary radial air inlet is delimited by two sidewalls that extend in a direction at an acute angle with a radial direction of the peripheral wall. In still another embodiment, the auxiliary radial air inlet has a width that decreases inward.

In yet another embodiment, a plurality of equispaced auxiliary radial air inlets are defined in the peripheral wall and adjacent to the first sidewall delimiting the radial air outlet. Each auxiliary radial air inlet has a width that decreases inward. Two sidewalls delimiting each auxiliary radial air inlet are parallel to each other. In still another embodiment, the peripheral wall further includes a plurality of extensions for the auxiliary radial air inlets. The extensions project from an inner face of the peripheral wall and extend along an air-driving direction of the impeller.

Other objects, advantages and novel features of this invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a conventional centrifugal blower;

FIG. 2 is an exploded view of a first embodiment of a centrifugal blower in accordance with the present invention;

FIG. 3 is a top sectional view of the centrifugal blower in FIG. 2;

FIG. 4 is an exploded perspective of a second embodiment of the centrifugal blower in accordance with the present invention;

FIG. 5 is an exploded perspective view of a third embodiment of the centrifugal blower in accordance with the present invention;

FIG. 6 is a top sectional view of the centrifugal blower in FIG. 5;

FIG. 7 is a top sectional view of a fourth embodiment of the centrifugal blower in accordance with the present invention; and

FIG. 8 is a top sectional view of a fifth embodiment of the centrifugal blower in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention are now to be described hereinafter in detail, in which the same reference numerals are used in the preferred embodiments for the same parts as those in the prior art to avoid redundant description.

Referring to FIGS. 2 and 3, a first embodiment of a centrifugal blower in accordance with the present invention comprises a housing 1, a cover 2, and an impeller 3. The housing 1 includes a peripheral wall 12 defining an inner space 10 in which the impeller 3 is rotatably mounted. The peripheral wall 12 further includes a radial air outlet 11 communicated with the inner space 10 and an auxiliary radial air inlet 13 that is also communicated with the inner space 10. An eccentric axle tube 101 is mounted in the inner space 10, and the impeller 3 is rotatably mounted on the eccentric axle tube 10.

The radial air outlet 11 is located at a side of the inner space 10. The peripheral wall 12 is substantially a snail shell-like structure surrounding the inner space 10. The auxiliary radial air inlet 13 may be circular or square in section. Preferably, the auxiliary radial air inlet 13 is in the form of a rectilinear slit located adjacent to the radial air outlet 11. A sectional area of the auxiliary radial air inlet 13 is smaller than that of the radial air outlet 11. Thus, the air inlet function of the auxiliary radial air inlet 13 is distinctive from the air outlet function of the radial air outlet 11.

The impeller 3 is aligned with an axial air inlet 21 of the cover. The impeller 3 includes a hub 31, an annular plate 32 extending from a periphery of the hub 31, and a plurality of blades 33 formed on a side of the annular plate 32. The impeller 3 is eccentrically mounted in the inner space 10. The radial air outlet 11 is delimited by a first sidewall 15 and a second sidewall 16 that are two opposed end portions of the peripheral wall 12. A portion of the peripheral wall 12 adjacent to the first sidewall 15 is an air-driving starting point. Another portion of the peripheral wall 12 adjacent to the second sidewall 16 is an air-driving end point. The air-driving starting point is closer to impeller 3 than the air-driving end point, as shown in FIG. 3. The auxiliary radial air inlet 13 is preferably adjacent to the air-driving starting point adjacent to the first sidewall 15 delimiting the radial air outlet 11.

As illustrated in FIG. 3, when the impeller 3 turns, axial airflow is sucked by the blades 33 of the impeller 3 into the inner space 10 via the axial air inlet 21 of the cover 2. The air-driving effect by the blades 33 of the impeller 3 creates a suction force that sucks ambient air adjacent to the auxiliary radial air inlet 13 into the inner space 10 via the auxiliary air inlet 13. In other words, the ambient air adjacent to the auxiliary radial air inlet 13 is sucked into the inner space 10 in the form of a radial airflow. The overall air inlet amount is increased and the wind pressure in the inner space 10 is increased.

During rotation of the impeller 3, since the sectional area of the auxiliary radial air inlet 13 is much smaller than that of the radial air outlet 11, the auxiliary radial air inlet 13 can only allow airflow to enter the inner space 10 and not allow exit of airflow. Leakage of air is avoided. The airflow is outputted via the radial air outlet 11. Thus, the centrifugal blower in accordance with the present invention may use the axial airflow above the cover 2 as well as the auxiliary radial airflow surrounding the peripheral wall 12 to proceed with heat dissipation for an object such as a fin. The overall air outlet amount is increased and the heat-dissipating effect is improved.

FIG. 4 illustrates a second embodiment of the centrifugal blower in accordance with the present invention. In this embodiment, a plurality of auxiliary radial air inlets 13′ are defined in the peripheral wall 12 adjacent to the first sidewall 15 delimiting the radial air outlet 11. Each auxiliary radial air inlet 13′ is inclined. Preferably, the auxiliary radial air inlets 13′ are equispaced and substantially parallel to one another. By this arrangement, the more radial auxiliary airflows can be sucked into the inner space 10 via the auxiliary radial air inlets 13′. All of the overall air inlet amount, the wind pressure, and the overall air outlet amount are increased.

FIGS. 5 and 6 illustrate a third embodiment of the centrifugal blower in accordance with the present invention. In this embodiment, a plurality of auxiliary radial air inlets 13″ are defined in the peripheral wall 12 adjacent to the first sidewall 15 delimiting the radial air outlet 11. Further, each of two sidewalls 131 and 132 delimiting each auxiliary radial air inlet 13″ extends in a direction at an acute angle with a radial direction of the peripheral wall 12, while the sidewalls (not labeled) delimiting the auxiliary radial air inlet 13 in the first embodiment extend along the radial direction. As illustrated in FIG. 6, the auxiliary radial air inlets 13″ are equispaced and the sidewalls 131 and 132 are substantially parallel to one another. By this arrangement, more radial auxiliary airflows can be sucked into the inner space 10 via the auxiliary radial air inlets 13″. All of the overall air inlet amount, the wind pressure, and the overall air outlet amount are increased.

FIG. 7 illustrates a fourth embodiment of the centrifugal blower in accordance with the present invention modified from the third embodiment. In this embodiment, a width of each auxiliary radial air inlet 13″ decreases inward. This allows smoother air suction and lowers the air suction noise. The auxiliary radial air inlets 13″ are further distinctive from the radial air outlet 11 in structure by the sidewalls 131 and 132 delimiting each auxiliary radial air inlet 13″.

FIG. 8 illustrates a fifth embodiment of the centrifugal blower in accordance with the present invention modified from the third embodiment. In this embodiment, a portion of the inner face of the peripheral wall 12 adjacent to the first sidewall 15 delimiting the radial air outlet 11 includes a plurality of extensions 14 that extend along the air-driving direction of the impeller 3. This provides the auxiliary radial air inlets 13″ with smoother air suction effect while lowering the air suction noise. Further, The auxiliary radial air inlets 13″ are further distinctive from the radial air outlet 11 in structure by the extensions 14.

While the principles of this invention have been disclosed in connection with specific embodiments, it should be understood by those skilled in the art that these descriptions are not intended to limit the scope of the invention, and that any modification and variation without departing the spirit of the invention is intended to be covered by the scope of this invention defined only by the appended claims. 

1. A centrifugal blower comprising: a housing comprising a peripheral wall delimiting an inner space, the peripheral wall further including a first sidewall and a second sidewall respectively at two ends thereof, a radial air outlet being defined between the first sidewall and the second sidewall of the peripheral wall; a cover including an axial air inlet communicated with the inner space of the housing; and an impeller rotatably mounted in the inner space of the housing and aligned with the axial air inlet; at least one auxiliary radial air inlet being defined in the peripheral wall and adjacent to one of the first sidewall and the second sidewall; wherein when the impeller turns, an axial airflow is sucked into the inner space via the axial air inlet and an auxiliary radial airflow is sucked into the inner space via said at least one auxiliary radial air inlet.
 2. The centrifugal blower as claimed in claim 1 wherein: a portion of the peripheral wall adjacent to the first sidewall delimiting the radial air outlet is an air-driving starting point; another portion of the peripheral wall adjacent to the second sidewall delimiting the radial air outlet is an air-driving end point; and said at least one auxiliary air inlet is adjacent to the air-driving starting point.
 3. The centrifugal blower as claimed in claim 2 wherein the housing is a snail shell-like structure and wherein the impeller is eccentrically mounted in the inner space.
 4. The centrifugal blower as claimed in claim 3 wherein the first sidewall delimiting the radial air outlet is closer to the impeller than the second sidewall delimiting the radial air outlet.
 5. The centrifugal blower as claimed in claim 1 wherein said at least one auxiliary radial air inlet is a rectilinear slit.
 6. The centrifugal blower as claimed in claim 1 wherein said at least one auxiliary radial air inlet is an inclined slit.
 7. The centrifugal blower as claimed in claim 1 wherein said at least one auxiliary radial air inlet is delimited by two sidewalls that extend in a direction at an acute angle with a radial direction of the peripheral wall.
 8. The centrifugal blower as claimed in claim 1 wherein said at least one auxiliary radial air inlet has a width that decreases inward.
 9. The centrifugal blower as claimed in claim 2 wherein a plurality of equispaced auxiliary radial air inlets are defined in the peripheral wall and adjacent to the first sidewall delimiting the radial air outlet.
 10. The centrifugal blower as claimed in claim 9 wherein each said auxiliary radial air inlet has a width that decreases inward.
 11. The centrifugal blower as claimed in claim 9 wherein two sidewalls delimiting each of said auxiliary radial air inlets are parallel to each other.
 12. The centrifugal blower as claimed in claim 9 wherein the peripheral wall further includes a plurality of extensions for the auxiliary radial air inlets, the extensions projecting from an inner face of the peripheral wall and extending along an air-driving direction of the impeller. 